#define _CRT_SECURE_NO_WARNINGS 1
#include<iostream>
#include"string.h"
#include<iostream>
using namespace std;
int main()
{
	//kl::string s1 = "hello world";
	//s1.push_back('x');
	//cout << s1.c_str() << endl;
	//s1.push_back("adoiioaoi");
	//cout << s1.c_str() << endl;
	//s1.insert(0, '=');
	//cout << s1.c_str() << endl;
	//s1[1];
	//const kl::string s2 = "hello world";
	//cout << s2.c_str() << endl;
	//s2[1];
	kl::string s3("hello world");
	s3.insert(2, "xxxx");
	cout << s3.c_str() << endl;

	return 0;
}